Concentric grinding machine



2,694,&83

Nov. 23, 1954 H. E. BALSIGER CONCENTRIC GRINDING MACHINE 5 Sheets-Sheet 1 Filed April 4, 1952 INVEN TOR. $95 042 .5. fiflLS/GEA Nov. 23, 1954 H. E. BALSIGER CONCENTRIC GRINDING MACHINE 5 Sheets-Sheet 2 Filed April 4, 1952 3, 95 H. E. BALSIGER CCNCENTRIC GRINDING MACHINE Filed April 4, 1952 5 Sheets-Sheet 3 l= ig-g INVENTOR. #419010 [Ems/65,?

ATTORNEY Nov. 23, 1954 H. E. BALSIGER CONCENTRIC GRINDING MACHINE 5 Sheets-Sheet 4 Filed April 4, 1952 INVENTOR. M42040 5. fiHLS/GEE 4Z Z ATTORNEY Nov. 23, 1954 H. E. BALSIGER CONCENTRIC GRINDING MACHINE Filed April 4, 1952 5 Sheets-Sheet 5 INVENTOR. #mw. D 5,8191. was) 5 4 7"7'0F2/VEY United States Patent CONCENTRIC GRINDING MACHINE Harold E. Balsiger, Waynesboro, Pa., assianor to Landis Tool Company, Waynesboro, Pa.

Application April 4, 1952, Serial No. 280,509

14 Claims. (Cl. 51-103) This application is a continuation in part of my application Serial No. 79,420, filed March 3, 1949, now abandoned. This invention relates to apparatus for grinding work pieces wherein the surface to be ground must be maintained concentric with another surface thereof.

Previous machines provided for this purpose have consisted of means for supporting the work piece on its periphery while rotating it by means of a conventional headstock with the ends of the work piece being gripped frictionally by resiliently pressed discs or equivalent devices on the headstock and footstock to grind another external surface such as a groove. While improved versions of this apparatus have been made, they still require positive or resilient means to hold the work against the driving member on the headstock. The principal disadvantage of this type of apparatus lies in the time required to remove a finished work piece and replace it with an unground piece due to the necessity of operating the footstock each time the work piece is changed.

Another disadvantage of this type of apparatus is the fact that the peripheral surface to be ground is also the surface on which the work is supported. As the work becomes smaller in diameter this position, relative to the work rest and the grinding wheel and also to the headstock, changes, thus complicating the problem of maintaining accuracy. In addition to these disadvantages, there is nothing in this method to insure concentricity between the internal and external surfaces of a ring shaped work piece.

It is, therefore, an object of this invention to provide means for supporting work pieces on a surface to which the ground surface must be held concentric and rotating the work piece thereon solely by the headstock about an axis offset from the axis of the headstock spindle in a direction downwardly and toward the grinding wheel.

A further object is to provide means for supporting work pieces on an internal surface when it is desired to hold the external surface to be ground concentric thereto.

A further object is to provide a magnetic chuck utilizing permanent magnets for-rotating the work piece.

A further object is to provide means for supporting a work piece on one surface for grinding on another surface and rotating the work piece through a third surface.

A further object is to provide means for loading and unloading a work piece which also supports the work piece during a machine operation.

Other objects will become apparent as the description proceeds.

In the drawings,

Figure l is a plan view of a conventional grinding machine showing one form of my invention. Figure 2 is a partial end elevation showing the method of supporting a work piece during a grinding operation.

Figure 3 is a plan elevation of a setup utilizing this invention for simultaneously grinding an internal and an external surface concentric with one another and with a third surface.

Figure 4a discloses the first step in a method of grinding concentric surfaces.

Figure 4b shows the second step in which the internal surface on which the work is to be supported during the grinding operation is ground true.

Figure 4c shows the third step in which the work is driven through one of the surfaces prepared in the first step, supported on the internal surface prepared in the (ill "ice

second step, and ground on an external peripheral surface which must be concentric with said internal surface.

Figure 4d is a partial end elevation of the arrangement of parts shown in Figure 4c.

Figure 5a is the first step in another method and is similar to Figure 4a.

Figure 5b is the second step consisting of grinding the external surface of a work piece.

Figure 5c shows the means for driving the work piece through one end surface only while grinding an internal peripheral surface thereof.

Figure 5d is an end elevation of Figure 50 showing the means for supporting the external surface of the work piece while the internal surface is ground concentric thereto.

Figure 6 is a partial plan view showing apparatus for facilitating the placing of the work in and removing it from the. machine.

Figure 7 is an end elevation of the structure disclosed in Figure 6.

Figure 8 is a front view of the work guide plate.

Figure 9 is a wiring diagram.

In the drawings, Figure l, numeral 10 indicates the wheelbase of a grinding machine; 11, a grinding wheel rotatably mounted on spindle 12 which is rotatably supported in said wheel base. Wheel 11 is driven by motor 13 through motor pulley 14, belts 15 and spindle pulley 16. Headstock is mounted on work carriage 21 and includes a work drive motor 22 operable through pulley 23, belts 24 and spindle pulley 25 to drive the headstock spindle 26. A magnetic chuck consisting of a body member having permanent magnets 31 inserted therein is mounted on the end of said spindle. A work piece 35 is held by said magnets against stop buttons 36. Said buttons protrude beyond the surface of said magnets. Their principal function is to hold the work out of contact with the magnets when the magnetic material is soft and offers lower resistance to abrasion. When hard material is used for the magnets, these buttons are unnecessary.

A footstock has a spindle 41 which may be inserted in a work piece. Peripherally spaced protruding shoes 42 and 43 on the end of said spindle then serve to support the work piece on the internal surface thereof while the work piece is rotated by said headstock through magnets 31 engaging the end surface of the work piece while a grinding operation is performed on the external peripheral surface thereof. This method for means of supporting the work piece is disclosed more clearly in Figure In the arrangement shown in Figure 3 the work piece 35 has been previously prepared by grinding the external peripheral surface thereof. In this particular arrangement the prepared surface is supported on peripherally spaced shoes and 51 and the work is held endwise and rotated by the magnetic chuck 30 on headstock spindle 26. An internal grinding wheel grinds the internal surface concentric to the previously prepared external surface.

The method disclosed in Figures 4a and 4b inclusive consists of steps of grinding the end surface of a work piece 35 parallel to the angular faces of grinding wheels and 66.

Figure 4b discloses the second step which consists in supporting and rotating the work by any suitable means while grinding the internal surface round. Figures 4c and 4d show the third step of driving the work piece through one of the surfaces ground in the first step supporting the work piece on the internal surface ground in the second step, and grinding an external peripheral surface concentric to said internal surfaces.

Figure 5a shows the first step. This first step is similar to that shown in Figure 4a.

Figure 5b discloses the second step of this method which consists of grinding the external peripheral surface of the work pece. While the method shown is a centerless method, the center type method can be used if desirable or necessary.

Figures 5c and 5d show the third step in which the work piece is driven through one of the end faces prepared in the first step supported by shoes 50 and51 in contact with the surface prepared in the second step while the internal grinding wheel 70 grinds a groove on the inside of said ring, the inside of said work piece being concentric with the external surface thereof.

Figures 6 and 7 disclose an improved means for placing a work piece in and removing it from the machine. This improved means consists of an arm 80 pivotally mounted at 81 on the bracket 82 attached to work carriage 21. At the outer end of the arm 80 and axially parallel with the headstock is a stub arbor 85 having peripherally spaced radially projecting shoes 86 and 87 above and below the horizontal respectively thereof on which a ring-like work piece 35 is supported. A work piece may be placed on this device either by hand or by suitable automatically operated means. On the other side of arm 80 is a handle 90 for moving the arm about its pivot to operative position relative to the grinding wheel in which position it is gripped by magnetic chuck 3%}. In moving from the loading position to the working position, the work piece is guided into engagement with said chuck by a guide plate 95, the surface of which is flush with the surface of the chuck 30. Stops .97 on the arms 80 and 98 on bracket 82 locate said arm and work piece 35 in grinding position. Stops 99 on arm 80 and 100 on bracket 82 limit the movement of said arms away from operative position.

A limit switch 110 is mounted on carriage 21 and has a roller on its actuating arm 113 in the path of arm 79 attached to pivot shaft 81. Said switch is normally open and when actuated by arm 79 in moving a Work piece into grinding position, it completes a circuit to energize a solenoid valve 111 which is thus shifted to position to direct fluid under pressure to one end of the feed cylinder 112 to move the wheel base and grinding wheel 11 forward to grinding position.

Operation in the apparatus shown in Figure l, a Work piece is placed on the chuck and held in position by permanent magnets 31. The inside of the work piece has been previously ground and the present operation is to grind the groove in the external surface. The footstock is then moved to the left to such position that spindle 41 with the work supporting shoes 42 and 43 may be moved into and out of the bore of the work piece by means of operating lever 44. However, the preferred means for supporting the work is shown in Figures 6 and 7.

in the apparatus shown in Figures 6 and 7, the work piece is placed on the stub arbor 85 and arm 30 is then moved downwardly to carry the work piece into operative relation with the chuck 30. Guide plate 95, which is attached to the headstock, has a cam shaped surface 96 at the upper end thereof so that if the work piece is not on the arbor 85 far enough, this surface will serve to m ve said work piece axially and the remainder of the guide plate will serve to hold the work piece in a position flush with the surface of the locating members 36 on said chuck. Stop 97 on arm 80 engages stop 98 on bracket 82 so that the work piece is peripherally located relative to the headstock. The headstock spindle 26 may be rotated continuously since the work piece may be placed on the chuck or removed therefrom without stopping rotation thereof. With the work piece on the chuck and rotated at the proper rate, the grinding wheel may be moved into contact therewith by any suitable mechanism. During the grinding operation, the position of the work is determined by the shoes 86 and 87 on arbor 85. The center of said arbor is offset below the center of the headstock spindle and slightly in the direction of the grinding wheel. The effect of this offset relation is that the rotating chuck 30 tends to hold the work piece firmly in engagement with the shoes 86 and 87. After the work piece has been ground to size, the arm 80 is lifted to slide the work piece off the chuck and return it to a position in which it can be removed from arbor 85 and an unground work piece placed thereon. The wiping movement of the work as it is removed from the chuck helps to keep the surface of the chuck free of metal or abrasive particles which would interfere with the accuracy of the grinding operation.

In Figure 3 a work piece having a previously ground outside diameter is supported on said previously ground surface by angularly spaced shoes and 51. Since there is to be no change in this outside diameter during the grinding operation, an internal grinding wheel may grind the internal surface, and an external grinding wheel 'said groove and said internal surface will be concentric with the previously ground outside diameter. During this operation, as in all the operations described herein, the work is driven through one of its end faces by magnetic chuck 30.

I claim:

1. In a grinding machine for grinding the external cylindrical surface ringlike work pieces, a grinding wheel and means to rotate same, a work drive spindle and means for rotating same, a work rest member having peripherally spaced work engaging shoes thereon and mounted to support and locate a work piece on the internal surface thereof with its axis spaced from that of said spindle for rotation about an axis offset from the axis of said work drive spindle, and means on said headstock spindle for effecting a uniform holding and rotating action of said work piece against said work rest during a grinding operation on the external surface thereof, including a magnetic chuck comprising one or more permanent magnets.

2. In a grinding machine, a grinding wheel and means to rotate same, a work drive spindle and means for rotating same, a work rest member mounted to support a work piece for rotation about an axis below the axis of said spindle and offset therefrom in the direction of said grinding wheel, and having means comprising peripherally spaced shoes for engaging and supporting said work piece on the internal surface thereof and means on said spindle for rotating said work piece about said firstmentioned axis during a grinding operation on the external surface thereof.

3. In a grinding machine for grinding ringlike work pieces, a grinding wheel and means to rotate same, awork drive spindle and means for rotating same, a magnetic chuck on said spindle for rotating a work piece, a work rcst comprising a base, a work supporting member slidahiy mounted on said base, work engaging shoes peripherally spaced on said work supporting member for engaging the internal surface of said work piece, said supporting member being offset radially from the axis of said spindle so that said work piece is urged against said work engaging shoes, and means for moving said Work supporting member axially into and out of operative relation with said work piece.

4. In a grinding machine for grinding ringlike work pieces, a grinding wheel and means to rotate same, a work drive spindle and means for rotating same, a work rest member having peripherally spaced work engaging shoes to support and locate a work piece on the internal surface thereof for rotation about an axis offset from the axis of said work drive spindle and means for exerting a uniform holding and rotating action of said work piece against said work rest during a grinding operation including a magnetic chuck.

5. In a grinding machine for grinding ringlike Work pieces, a grinding wheel and means to rotate same, a work drive spindle and means for rotating same, a magnetic chuck on said spindle for holding and rotating a work piece, work supporting means comprising a bracket, an arm pivotally mounted thereon for movement in a plane transversely of said work drive spindle, a work supporting device on said arm having Work engaging portions peripherally spaced thereon for engaging the internal surface of said work piece, stops for locating said arm in loading and unloading position and in grinding position, whereby said work piece is moved into and out of operati e relati n. with said chuck in a path transversely of the axis of rotation thereof.

6. In a grinding machine for grinding cylindrical work pieces having an internal and an external surface, a grinding wheel and means for rotating same, a work drive spindle and means for rotating same, a magnetic ch rk on said spindle for holding and rotating a Work piece, work supporting means mounted for movement in a plane transversely of said work drive spindle and including a stub shaft for supporting a work piece, said shaft having work engaging portions peripherally spaced thereon for engaging the internal surface of a work piece, whereby said work piece is moved into and out of operative relation with said chuck in a path transversely of the axis rotation thereof.

7. In a grinding machine for grinding cylindrical work pieces having an internal and an external surface,

' a grinding wheel and means for rotating same, a work drive spindle and means for rotating same, a magnetic piece, Work supporting means mounted for movement in a plane transversely of said work drive spindle and including a stub shaft having peripherally spaced work engaging portions thereon for supporting a work piece during the loading and grinding operations and stops for locating said transverse moving means in said loading and grinding positions.

8. In a grinding machine for grinding cylindrical work pieces having an internal and an external surface, a grinding wheel and means for rotating same, a work drive spindle and means for rotating same, a magnetic chuck on said spindle for holding and rotating a work piece, work supporting means including a stub shaft having peripherally spaced portions thereon for engaging said internal surface and rotatably supporting the work piece during a grinding operation, said work supporting means being movable transversely of the axis or rotation of said chuck to slide a work piece into and out of operative relation with said magnetic chuck.

9. In a grinding machine for grinding the external surface of ring like work pieces, a grinding wheel support, a grinding wheel rotatably mounted thereon, means for supporting said work pieces during a grinding operation comprising a work support, means for rotatably supporting a work piece thereon including a nonrotatable arbor having peripherally spaced work engaging surfaces thereon for engaging the internal surface of said work piece during a grinding operation on the external surface thereof and means for rotating said work piece.

10. In a grinding machine for grinding the external cylindrical surface of ring like work pieces, a grinding wheel support, a grinding wheel rotatably mounted thereon, means for rotating said grinding wheel, a headstock, a spindle rotatably mounted therein and having means for rotating same, a work supporting member comprising a nonrotatable arbor having peripherally spaced work engaging surfaces thereon to support and locate a work piece on the internal surface thereof whereby the external surface may be ground concentric with the internal surface.

11. In a grinding machine for grinding the external cylindrical surface of ring like work pieces, a bed, a wheel support mounted thereon, a grinding wheel rotatably mounted on said support, a work carriage mounted on said bed, means for rotatably supporting a work piece on said carriage including a headstock, a headstock spindle rotatably mounted therein, a chuck on said spindle for driving a work piece by engagement with the end surface thereof and permitting radial movement of the work piece thereon, a nonrotatable arbor having peripherally spaced Work engaging surfaces thereon, whereby to maintain a fixed wall thickness of the work piece between said arbor and said grinding wheel and thus maintain the external surface of the work piece concentric with the internal surface thereof.

12. In a grinding machine for grinding the external peripheral surface of a ring like work piece, a stationary work rest disposed within the work piece and having devices contacting the inner surface of the work piece at peripherally spaced points for supporting the work piece for rotation about its own center, means for rotating said work piece, a grinding wheel for engaging the periphery of said ring like work piece, and means for rotating said grinding wheel about an axis parallel to the axis of the work piece.

13. In a grinding machine for grinding ringlike work pieces, a grinding wheel and means to rotate same, a work drive spindle and means for rotating same, a magnctic chuck on said spindle for rotating a work piece, a work rest comprising a base, a work supporting member movably mounted on said base, work engaging shoes peripherally spaced on said work supporting member for engaging the internal surface of said work piece, and means for effecting relative axial movement of said work supporting member and said work piece into and out of operative relation.

14. In a grinding machine for grinding cylindrical work pieces having an internal and an external cylindrical surface, a grinding wheel and means for rotating same, a Work drive spindle and means for rotating same, a magnetic chuck on said spindle for holding and rotating a work piece, work supporting means having peripherally spaced portions thereon for engaging one of said surfaces and rotatably supporting the work piece thereon during a grinding operation, said work supporting means being pivotally mounted and movable transversely in a path adjacent to and parallel with the face of said chuck to slide a work piece into and out of operative engagement with said magnetic chuck.

References Cited in the file of this patent 414,533 Great Britain Aug. 9, 1934 

